Four male volunteers (43 to 53 years old; 3 black, 1 white) were enrolled, dosed, and monitored. During the initial three day washout period, total dithiocarbamate excretion ranged from undetectable to 70.7 mol. However, for all four volunteers, levels fell below the limit of detection (0.124 mol/8 hour) by at least 16 hrs prior to the first broccoli sprout dose. In all four subjects, and for all three preparations, urinary dithiocarbamate excretion peaked in the first four hours for all but one subject, whose excretion after glucosinolates peaked in the 4-8 hour collection. Despite the fact that the broccoli sprout glucosinolates and isothiocyanates doses were equal (100 mol), the isiocyanate preparation yielded nearly seven times more urinary dithicarbamates (89.6 1 5.88 mol, range 83.9 - 95.9) than did the glucosinolate preparation (13.1 1 1.65 mol, range 11.3 - 15.7). This difference is statistically significant (p = 0.0003, two-tailed paired t-test). Although total dithiocarbamate excretion after the daikon preparation apparently exceeded the dose by a factor of up to 2.9, its contribution to the broccoli isothiocyanate results, at 3% of total excretion, remain negligible.